Adjustable seat back cushion



FIG. 1 is a front perspective view of an adjustable seat back cushion showing my design;

FIG. 2 is a front elevational view thereof on a reduced scale;

FIG. 3 is a left side elevational view on a reduced scale;

FIG. 4 is a right side elevational view on a reduced scale;

FIG. 5 is a rear elevational view on a reduced scale;

FIG. 6 is a top plan view on a reduced scale;

FIG. 7 is a left side elevational view on a reduced scale showing the central cushion expanded and the two outer cushions collapsed; and

FIG. 8 is a left side elevational view of the adjustable seat back cushion of FIG. 1 wherein the upper cushion is shown collapsed, the central cushion is shown partly expanded and the bottom cushion is shown fully expanded. 

The ornamental design of an adjustable seat back cushion, as shown and described. 